This application references Disclosure Document No. 478,776 filed Aug. 21, 2000.
The invention generally resides in the field of instruments for measuring and displaying the level of a liquid in a containment vessel or a drilled well. A unique sensor system is employed to monitor, obtain depth (height) of the liquid (water) and transmit for display the determined depth (height) information to the user.
Over years varying types of instrumentation have been used to gauge the water level and available pressure in drilled wells so as to be able to determine water flow rate and capacity. The present invention enables the instrumentation and the apparatus needed to make such measurements.
Earlier devices for measuring water flow rate and well capacity were complicated and cumbersome to install and to maintain. One such device is that described in U. S. Pat. No. 5,105,662 [Marsh, et al.] which is suited for measuring the liquid level in a fixed dimension containment vessel, i.e. a fuel tank. Marsh, et al. discloses a system for measuring the level of a liquid material by direct pressure of the subject liquid against a pressure sensor balanced against a reference pressure in an air column. The reference pressure is based upon the static air pressure in the containment vessel holding the liquid as registered by the compression of the air column.
A second patent, U. S. Pat. No. 5,207,251 [Cooks], describes an automatic fill control for a liquid holding tank which uses a pressurized sensor to determine both flow rate and liquid level height. This is accomplished utilizing a gas bubble (column) as the correlating measurement device. Cooks describes a gas column as containing Nitrogen (N2) which uses the gravimetric pressure of the liquid whose height (depth) is to be measured by being exerted against a second (pressure conducting) fluid. The second fluid, in turn, exerts pressure against a sensor. In this manner the primary pressure conducting fluid has its level of compression controlled by the pressure exerted against it by the fluid in the containment vessel which is used as a threshold for controlling a dispensing valve to add fluid to the vessel.
Finally, U. S. Pat. No. 5,901,603 [Fiedler] describes a hydrostatic pressure sensing device for measuring the height (depth) of a liquid in a containment vessel. The particular apparatus utilized comprises a pump for supplying pressurized air to a supply tank which is maintained at a 1.5 psi differential above the detected liquid pressure. Exiting the supply tank is an air supply line which is applied to one side of the hydrostatic pressure sensor. A temperature compensated solid state pressure transducer bleeds off or increases pressure by way of a manifold to maintain the appropriate pressure in the air supply. The reference side of the pressure sensor vents to the outside (ambient) air. The pressurized air supply line and the air reference ports are tied together through the manifold, also referred to as a drift compensation valve, so that the differential pressure transducer prevent drift by automatic correction and correlation of the pressures between the ambient (outside) air and the pressurized air column in the air supply line as applied to the pressure sensor which is submerged below the fluid level in the containment vessel.
In all of the foregoing devices, the complexity of the balancing of reference pressures against the variant pressures of the contained liquid require intermediate elements to counteract or to convey the pressure in order to obtain accurate results. The present invention creates a unique and simple series of elements for accurately determining the height of the water level in a drilled well and to instantaneously display, or continually record, that level for immediate of later use by the water user.
It is an object of the present invention to provide a simple system for measuring well water depth (height) utilizing a control circuit for determining the depth of the water by measuring the pressure of the water in a selectably dimensioned column and display such result instantaneously to the user.
It is also an object of the present invention to have the capacity to measure more than one well water level and to provide output control signals for communication with multi-purpose computers or to water flow rate controllers to regulate flow against demand.
It is a further object of the present invention to provide useful information to the display in the form of water flow rate (usage) in gallons, liters or feet per time segment, and to provide this information on a single inquiry or continuing inquiry basis.
It is a still further object of the present invention to provide a programmatically controlled water level measurement device which is capable of communicating with other computing devices as well as controlling and monitoring a plurality of measurements of for each of a plurality of wells.
Other objects will appear hereinafter.
A well water level sensing apparatus using a pressurized air column in contact with the water at its distal end to derive a correlated value dependent upon the length of the air column which is converted for retrieving stored water levels from memory and displaying the retrieved water levels on a visual display. The water level sensing apparatus may be manually initiated or programmatically controlled for continual monitoring.
The program control can be described as follows. Measuring the level of water in a well utilizing pressurized air comprises the steps of initializing a means for controlling the sensing and monitoring of the water level measurement which first reduces pressure in an air column inserted into a well to existing ambient pressure by closing a first valving means located between a pressure sensor and the air column to exhaust and isolate the air column. A second valving means located between a pump and an air tank of substantially equal volume as the air column is opened and the pump to charge the air tank to a predetermined measurement pressure is started. The second valving means is closed to isolate the air tank as the measurement pressure is detected by the pressure sensor. The first valving means is opened equalizing the measurement pressure between the air tank and the air column to obtain a direct pressure of the well water against the distal end of the air column. The pressure of the well water exerted against the air column is detected by the pressure sensor and the water level is calculated from the resultant sensed pressure. The calculated water level is then displayed on a visual display for viewing by a user. This method may further comprise continually sensing and monitoring the pressure of the well water exerted against the air column by repeating the sequence at preset periodic times.
The means for controlling the sensing and monitoring of the water level measurement may include a programmable computing device for controlling the sequence for measuring the well water depth using pressurized air. The controller may receive instructions over a communications channel from a multi-purpose computer to perform the well water depth measurements and providing well water depth measurements to said computer over said communications channel. The method may also include selectively sensing and monitoring the well water depth of a plurality of wells by repeating the measurement sequence for each well water depth measurement for each one of the plurality of wells.
The measurement may be accomplished by a number of elements for measuring well water depth using pressurized air which include a means for controlling the sensing and monitoring of water level measurements subject to program control for sequencing the order of operation of a first and a second valving means, an air tank, an air column, a pressure sensor, and a visual display. The first valving means is operatively connected between the pressure sensor and the air column, having its distal end inserted into a well, to reduce pressure in the air column to existing ambient pressure by exhausting said air and isolating the air column. The second valving means is operatively connected to a pump and an air tank of substantially equal volume as the air column, and to the pressure sensor, to couple the air tank to the air column upon the sensing of a predetermined measurement pressure being detected in the air tank by the pressure sensor. The pump is capable of charging the air tank to the predetermined measurement pressure. As above, the pressure sensor is capable of directly sensing the pressure of the well water exerted against the distal end of the air column, following the equalizing of the predetermined measurement pressure between the air tank and the air column, and to provide the sensed pressure to the controller for calculating the water level in the well from the sensed pressure. The controller will then display the calculated water level on the visual display.
The apparatus may be programmed for the controller to continually sense and monitor the pressure of the well water exerted against the distal end air column by repeating the sequence of operation at preset periodic times. The controller may also receive instructions over a communications channel from a multi-purpose computer to perform the well water depth measurements and provide well water depth measurements to said computer over said communications channel. The controller may also selectively sense and monitor the well water depth of a plurality of wells by repeating the sequence of operation for each well water depth measurement for each one of the plurality of wells.